Mr Adams has been questioned over the 1972 abduction and murder of Jean McConville.

Reuters: Eric Thayer, file photo

Irish republican leader Gerry Adams has received a death threat after being released from detention, his Sinn Fein party said.

The Police Service of Northern Ireland (PSNI) released Mr Adams yesterday after questioning him over the 1972 abduction and murder of Jean McConville.

Mr Adams strenuously denies any involvement in the killing.

After his release, police went to Mr Adams's house and told his wife Collette that criminals had made a serious threat against her husband's life, Sinn Fein said.

"I can confirm that the PSNI visited the homes of Gerry Adams and (fellow Irish republican) Bobby Storey last night to warn them of a credible threat against their lives," Sinn Fein justice spokesperson Raymond McCartney said in a statement.

No comment was immediately available from the PSNI.

Catholic and Protestant Northern Irish leaders, including the province's first and deputy first ministers Peter Robinson and Martin McGuinness, have received death threats in the past over their support of the peace process.

Mr Adams's arrest is among the most significant in Northern Ireland since a 1998 peace deal ended decades of tit-for-tat killings between Irish Catholic nationalists and mostly Protestant pro-British loyalists.

The Sinn Fein leader, who is a member of parliament in the Irish republic, has been dogged throughout his career by accusations from former IRA fighters that he was involved in its campaign of killings, a charge he has repeatedly denied.